Move condition in CollapsedBorderValue::Width() into constructor

This avoids the condition from being repeatedly checked.

Also tweek other methods to avoid unnecessary checks. Add test.

BUG=717128

Review-Url: https://codereview.chromium.org/2858143003
Cr-Commit-Position: refs/heads/master@{#469562}

third_party/WebKit/Source/core/BUILD.gn

@@ -1294,6 +1294,7 @@ source_set("unit_tests") {
     "html/track/vtt/VTTScannerTest.cpp",
     "input/EventHandlerTest.cpp",
     "inspector/ProtocolParserTest.cpp",
+    "layout/CollapsedBorderValueTest.cpp",
     "layout/ImageQualityControllerTest.cpp",
     "layout/LayoutBlockTest.cpp",
     "layout/LayoutBoxModelObjectTest.cpp",

third_party/WebKit/Source/core/layout/CollapsedBorderValue.h

@@ -49,25 +49,23 @@ class CollapsedBorderValue {
       : color_(0),
         width_(0),
         style_(kBorderStyleNone),
-        precedence_(kBorderPrecedenceOff),
-        transparent_(false) {}
+        precedence_(kBorderPrecedenceOff) {}
 
   CollapsedBorderValue(const BorderValue& border,
                        const Color& color,
                        EBorderPrecedence precedence)
       : color_(color),
-        width_(border.NonZero() ? border.Width() : 0),
+        width_(border.Style() > kBorderStyleHidden ? border.Width() : 0),
         style_(border.Style()),
-        precedence_(precedence),
-        transparent_(border.IsTransparent()) {
+        precedence_(precedence) {
     DCHECK(precedence != kBorderPrecedenceOff);
   }
 
-  unsigned Width() const { return style_ > kBorderStyleHidden ? width_ : 0; }
+  unsigned Width() const { return width_; }
   EBorderStyle Style() const { return static_cast<EBorderStyle>(style_); }
   bool Exists() const { return precedence_ != kBorderPrecedenceOff; }
   Color GetColor() const { return color_; }
-  bool IsTransparent() const { return transparent_; }
+  bool IsTransparent() const { return !color_.Alpha(); }
   EBorderPrecedence Precedence() const {
     return static_cast<EBorderPrecedence>(precedence_);
   }
@@ -80,8 +78,8 @@ class CollapsedBorderValue {
   bool VisuallyEquals(const CollapsedBorderValue& o) const {
     if (!IsVisible() && !o.IsVisible())
       return true;
-    return GetColor() == o.GetColor() && IsTransparent() == o.IsTransparent() &&
-           IsSameIgnoringColor(o);
+    return GetColor() == o.GetColor() && Width() == o.Width() &&
+           Style() == o.Style();
   }
 
   bool IsVisible() const { return Width() && !IsTransparent(); }
@@ -93,10 +91,9 @@ class CollapsedBorderValue {
 
  private:
   Color color_;
-  unsigned width_ : 24;
+  unsigned width_ : 25;
   unsigned style_ : 4;       // EBorderStyle
   unsigned precedence_ : 3;  // EBorderPrecedence
-  unsigned transparent_ : 1;
 };
 
 }  // namespace blink

third_party/WebKit/Source/core/layout/CollapsedBorderValueTest.cpp

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "core/layout/CollapsedBorderValue.h"
+
+#include "core/style/ComputedStyle.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace blink {
+
+TEST(CollapsedBorderValueTest, Default) {
+  CollapsedBorderValue v;
+  EXPECT_EQ(0u, v.Width());
+  EXPECT_EQ(kBorderStyleNone, v.Style());
+  EXPECT_FALSE(v.Exists());
+  EXPECT_EQ(kBorderPrecedenceOff, v.Precedence());
+  EXPECT_FALSE(v.IsVisible());
+
+  EXPECT_TRUE(v.IsSameIgnoringColor(v));
+  EXPECT_TRUE(v.VisuallyEquals(v));
+  EXPECT_TRUE(v.IsSameIgnoringColor(CollapsedBorderValue()));
+  EXPECT_TRUE(v.VisuallyEquals(CollapsedBorderValue()));
+}
+
+TEST(CollapsedBorderValueTest, SolidZeroWidth) {
+  auto style = ComputedStyle::Create();
+  style->SetBorderLeftWidth(0);
+  style->SetBorderLeftStyle(kBorderStyleSolid);
+  CollapsedBorderValue v(style->BorderLeft(), Color(255, 0, 0),
+                         kBorderPrecedenceCell);
+  EXPECT_TRUE(v.Exists());
+  EXPECT_EQ(0u, v.Width());
+  EXPECT_FALSE(v.IsTransparent());
+  EXPECT_FALSE(v.IsVisible());
+
+  EXPECT_TRUE(v.IsSameIgnoringColor(v));
+  EXPECT_TRUE(v.VisuallyEquals(v));
+  EXPECT_FALSE(v.IsSameIgnoringColor(CollapsedBorderValue()));
+  EXPECT_FALSE(v.IsSameIgnoringColor(
+      CollapsedBorderValue(ComputedStyle::Create()->BorderLeft(),
+                           Color(0, 255, 0), kBorderPrecedenceCell)));
+  EXPECT_TRUE(v.VisuallyEquals(CollapsedBorderValue()));
+}
+
+TEST(CollapsedBorderValueTest, SolidNonZeroWidthTransparent) {
+  auto style = ComputedStyle::Create();
+  style->SetBorderLeftWidth(5);
+  style->SetBorderLeftStyle(kBorderStyleSolid);
+  CollapsedBorderValue v(style->BorderLeft(), Color(), kBorderPrecedenceCell);
+  EXPECT_TRUE(v.Exists());
+  EXPECT_EQ(5u, v.Width());
+  EXPECT_TRUE(v.IsTransparent());
+  EXPECT_FALSE(v.IsVisible());
+
+  EXPECT_TRUE(v.IsSameIgnoringColor(v));
+  EXPECT_TRUE(v.VisuallyEquals(v));
+  EXPECT_FALSE(v.IsSameIgnoringColor(CollapsedBorderValue()));
+  EXPECT_TRUE(v.IsSameIgnoringColor(CollapsedBorderValue(
+      style->BorderLeft(), Color(0, 255, 0), kBorderPrecedenceCell)));
+  EXPECT_TRUE(v.VisuallyEquals(CollapsedBorderValue()));
+}
+
+TEST(CollapsedBorderValueTest, None) {
+  auto style = ComputedStyle::Create();
+  style->SetBorderLeftWidth(5);
+  style->SetBorderLeftStyle(kBorderStyleNone);
+  CollapsedBorderValue v(style->BorderLeft(), Color(255, 0, 0),
+                         kBorderPrecedenceCell);
+  EXPECT_TRUE(v.Exists());
+  EXPECT_EQ(0u, v.Width());
+  EXPECT_FALSE(v.IsTransparent());
+  EXPECT_FALSE(v.IsVisible());
+
+  EXPECT_TRUE(v.IsSameIgnoringColor(v));
+  EXPECT_TRUE(v.VisuallyEquals(v));
+  EXPECT_FALSE(v.IsSameIgnoringColor(CollapsedBorderValue()));
+  EXPECT_TRUE(v.IsSameIgnoringColor(
+      CollapsedBorderValue(ComputedStyle::Create()->BorderLeft(),
+                           Color(0, 255, 0), kBorderPrecedenceCell)));
+  EXPECT_TRUE(v.VisuallyEquals(CollapsedBorderValue()));
+}
+
+TEST(CollapsedBorderValueTest, Hidden) {
+  auto style = ComputedStyle::Create();
+  style->SetBorderLeftWidth(5);
+  style->SetBorderLeftStyle(kBorderStyleHidden);
+  CollapsedBorderValue v(style->BorderLeft(), Color(255, 0, 0),
+                         kBorderPrecedenceCell);
+  EXPECT_TRUE(v.Exists());
+  EXPECT_EQ(0u, v.Width());
+  EXPECT_FALSE(v.IsTransparent());
+  EXPECT_FALSE(v.IsVisible());
+
+  EXPECT_TRUE(v.IsSameIgnoringColor(v));
+  EXPECT_TRUE(v.VisuallyEquals(v));
+  EXPECT_FALSE(v.IsSameIgnoringColor(CollapsedBorderValue()));
+  EXPECT_FALSE(v.IsSameIgnoringColor(
+      CollapsedBorderValue(ComputedStyle::Create()->BorderLeft(),
+                           Color(0, 255, 0), kBorderPrecedenceCell)));
+  EXPECT_TRUE(v.VisuallyEquals(CollapsedBorderValue()));
+}
+
+TEST(CollapsedBorderValueTest, SolidNonZeroWidthNonTransparent) {
+  auto style = ComputedStyle::Create();
+  style->SetBorderLeftWidth(5);
+  style->SetBorderLeftStyle(kBorderStyleSolid);
+  CollapsedBorderValue v(style->BorderLeft(), Color(255, 0, 0),
+                         kBorderPrecedenceCell);
+  EXPECT_TRUE(v.Exists());
+  EXPECT_EQ(5u, v.Width());
+  EXPECT_FALSE(v.IsTransparent());
+  EXPECT_TRUE(v.IsVisible());
+
+  EXPECT_TRUE(v.IsSameIgnoringColor(v));
+  EXPECT_TRUE(v.VisuallyEquals(v));
+  EXPECT_FALSE(v.IsSameIgnoringColor(CollapsedBorderValue()));
+  EXPECT_FALSE(v.VisuallyEquals(CollapsedBorderValue()));
+
+  EXPECT_TRUE(v.IsSameIgnoringColor(CollapsedBorderValue(
+      style->BorderLeft(), Color(0, 255, 0), kBorderPrecedenceCell)));
+  EXPECT_FALSE(v.VisuallyEquals(CollapsedBorderValue(
+      style->BorderLeft(), Color(0, 255, 0), kBorderPrecedenceCell)));
+
+  EXPECT_FALSE(v.IsSameIgnoringColor(CollapsedBorderValue(
+      style->BorderLeft(), Color(255, 0, 0), kBorderPrecedenceTable)));
+  EXPECT_TRUE(v.VisuallyEquals(CollapsedBorderValue(
+      style->BorderLeft(), Color(255, 0, 0), kBorderPrecedenceTable)));
+}
+
+}  // namespace blink